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When computing the value on an edge, in certain cases LVI would fail to compute the value range 

in the predecessor block, leading to an incorrect conclusion for the edge value.  Found by inspection.

llvm-svn: 122908
This commit is contained in:
Owen Anderson 2011-01-05 21:37:18 +00:00
parent 7bdd440035
commit e86dacf449
1 changed files with 5 additions and 0 deletions
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5
llvm/lib/Analysis/LazyValueInfo.cpp
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@ -817,6 +817,11 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
if (!isTrueDest) TrueValues = TrueValues.inverse();
// Figure out the possible values of the query BEFORE this branch.
if (!hasBlockValue(Val, BBFrom)) {
block_value_stack.push(std::make_pair(BBFrom, Val));
return false;
}
LVILatticeVal InBlock = getBlockValue(Val, BBFrom);
if (!InBlock.isConstantRange()) {
Result = LVILatticeVal::getRange(TrueValues);